Enteric human adenovirus(HAdV),a common cause of acute viral gastroenteritis in children,frequently triggers spo-radic infections,nosocomial transmissions,and outbreaks in kindergarten settings.This study was aimed at investigating the molecular characteristics and genetic evolution of enteric HAdV among patients with acute gastroenteritis younger than 5 years in China,to pro-vide foundational data for disease prevention and control.A total of 8 074 stool samples were collected from hospitalized or outpatient children younger than 5 years with acute gastroenteritis in China during 2023.HAdV screening was conducted with real-time fluores-cence PCR.Positive samples were sequenced,then subjected to bioinformatics analysis including genotyping,homology assessment,and phylogenetic analysis with GenBank,BioAider,and MEGA11.0.A total of 370 samples(4.58%)tested positive for HAdV.Two enteric HAdV genotypes were identified:HAdV-F41(which predominated,at 98.09%)and HAdV-F40(1.90%).HAdV-F41 was the dominant genotype among patients with acute gastroenteritis younger than 5 years in China.Bioinformatics analysis indicated that the predominant HAdV lineages in China were lineage 1 and 2,whereas European lineage 3 showed no influence.Systematic and long-term surveillance of HAdV should help elucidate its diversity and evolutionary patterns in China,thereby providing scientific evi-dence for developing more effective prevention strategies.

This study investigated the full-genome molecular characteristics of a rotavirus vaccine-derived strain,G1P[8]geno-type A group rotavirus RVA/Human-wt/CHN/HN1140/2021/G1P[8](referred to as HN1140).The gene fragments of the HN1140 strain were amplified with reverse transcription-polymerase chain reaction(RT-PCR)combined with whole-genome primers to obtain the full genome sequence.Genotyping was performed with the online genotyping tool RotaC 2.0,and similarity and genetic evolution analyses for each gene segment were conducted in DNAstar5.1 and MEGA11.0 software.The genotype of the HN1140 strain was deter-mined to be G1-P[8]-I2-R2-C2-M2-A3-N2-T6-E2-H3.Phylogenetic analysis demonstrated that all 11 genomic segments clus-tered closely with the RotaTeq vaccine strains,sharing 99.7%-100%nucleotide sequence similarity.Notably,VP1,VP2,VP6,and NSP2-NSP5 segments showed 100%nucleotide identity with RotaTeq strains.Comparative genomic analysis identified 13 nucleotide and 8 amino acid substitutions between HN1140 and RotaTeq strains,localized within the VP7,VP4,VP1,VP2,VP3,and NSP1 segments.The HN1140 strain exhibited the genotype G1-P[8]-A3-T6-H3,which was consistent with the typical profile of a vaccine-derived reassortant.This strain demonstrated high genetic similarity to RotaTeq vaccine strains,with nucleotide sequence identity ranging from 99.7%to 100%.These findings suggested that HN1140 evolved from RotaTeq vaccine strains through genetic reassortment.

Enteric human adenovirus(HAdV),a common cause of acute viral gastroenteritis in children,frequently triggers spo-radic infections,nosocomial transmissions,and outbreaks in kindergarten settings.This study was aimed at investigating the molecular characteristics and genetic evolution of enteric HAdV among patients with acute gastroenteritis younger than 5 years in China,to pro-vide foundational data for disease prevention and control.A total of 8 074 stool samples were collected from hospitalized or outpatient children younger than 5 years with acute gastroenteritis in China during 2023.HAdV screening was conducted with real-time fluores-cence PCR.Positive samples were sequenced,then subjected to bioinformatics analysis including genotyping,homology assessment,and phylogenetic analysis with GenBank,BioAider,and MEGA11.0.A total of 370 samples(4.58%)tested positive for HAdV.Two enteric HAdV genotypes were identified:HAdV-F41(which predominated,at 98.09%)and HAdV-F40(1.90%).HAdV-F41 was the dominant genotype among patients with acute gastroenteritis younger than 5 years in China.Bioinformatics analysis indicated that the predominant HAdV lineages in China were lineage 1 and 2,whereas European lineage 3 showed no influence.Systematic and long-term surveillance of HAdV should help elucidate its diversity and evolutionary patterns in China,thereby providing scientific evi-dence for developing more effective prevention strategies.

This study investigated the full-genome molecular characteristics of a rotavirus vaccine-derived strain,G1P[8]geno-type A group rotavirus RVA/Human-wt/CHN/HN1140/2021/G1P[8](referred to as HN1140).The gene fragments of the HN1140 strain were amplified with reverse transcription-polymerase chain reaction(RT-PCR)combined with whole-genome primers to obtain the full genome sequence.Genotyping was performed with the online genotyping tool RotaC 2.0,and similarity and genetic evolution analyses for each gene segment were conducted in DNAstar5.1 and MEGA11.0 software.The genotype of the HN1140 strain was deter-mined to be G1-P[8]-I2-R2-C2-M2-A3-N2-T6-E2-H3.Phylogenetic analysis demonstrated that all 11 genomic segments clus-tered closely with the RotaTeq vaccine strains,sharing 99.7%-100%nucleotide sequence similarity.Notably,VP1,VP2,VP6,and NSP2-NSP5 segments showed 100%nucleotide identity with RotaTeq strains.Comparative genomic analysis identified 13 nucleotide and 8 amino acid substitutions between HN1140 and RotaTeq strains,localized within the VP7,VP4,VP1,VP2,VP3,and NSP1 segments.The HN1140 strain exhibited the genotype G1-P[8]-A3-T6-H3,which was consistent with the typical profile of a vaccine-derived reassortant.This strain demonstrated high genetic similarity to RotaTeq vaccine strains,with nucleotide sequence identity ranging from 99.7%to 100%.These findings suggested that HN1140 evolved from RotaTeq vaccine strains through genetic reassortment.

Objective:A genome-wide molecular characterization of FJ21351116, a strain of G3P[8]-E2 2021 collected in Fujian, China, was performed.Methods:Whole genome sequencing of FJ21351116 was performed using a high-sensitivity group A rotavirus whole genome sequencing method. Genomic characteriza-tion of the virus was assessed by nucleic acid sequence analysis using MEGA 11.0, Geneious 9.0.2 and DNASTAR software. Neutralization epitopes of VP7 and VP4 (VP8*) were analyzed using BioEdit v. 7.0.9.0 and PyMOL v. 2.5.2.Results:In this study, FJ21351116 was shown to be a G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype, and the result of phylogenetic tree showed that the VP7, VP4, VP3, and NSP2-NSP5 genes of the FJ21351116 strain were related to the equine-like DS-1-like G3P[8] genes that have been detected in Japan in recent years. VP6, VP1, VP2, and NSP1 genes are closely related to G2P[4] in most countries, especially in Singapore, suggesting that this strain was formed by genetic reassortment during the evolution of equine-like G3P[8] and G2P[4]. Evolutionary relationships between the VP7/VP4 genes of FJ21351116 and Rotarix and RotaTeq vaccines suggest that the multiple mutations in both VP7 and VP4 (VP8*) neutralizing antigenic epitopes and vaccine amino acid sites. It is hypothesized that the Rotarix and RotaTeq vaccines may be less effective against equine DS-1-like G3P[8] RVA, and the sequence differences with Rotarix are higher than those with RotaTeq.Conclusions:In this study, we found a rare case of DS-1-like G3P [8] RVA strain in China. Currently, horse-like DS-1-like G3P [8] RVA is relatively rare in China and may be poorly protected by vaccine strains, emphasizing the importance of continuous monitoring of RVA strains and the development of efficient and full-coverage RVA vaccines.

Rotavirus is one of the most common pathogens causing severe gastroenteritis in children under 5 years of age in the world. RV vaccination is the most effective measure to control rotavirus diarrhea in infants. The immune effect of RV vaccine is different in countries with different income levels. In this study, the factors affecting the immune effect of RV vaccine are systematically expounded, which provides reference for the research of RV vaccine and the formulation of immune strategy.